Engine starter gearing



A. R. ToBlAs 2,569,267

ENGNE STARTER GEARING Sept. 25, 1951 Filed June 9, 1950 f' @j 6 mm32:13a

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ATTORNE Y WITNESS:

Patented Sept. 225,y 1951 ENGINE STARTER GEARING Arthur n. Tobias,Elmira, N. Y., assigner to Beh# dix Aviation Corporation, ElmiraHeights, N. Y., a corporation of Delaware Application June 9, 1950,Serial No. 167,103

The present invention relates to engine starter gearing, and moreparticularly to'that type of drive in which the engagement of a drivepinion with an engine gear is secured by threaded traversing means.

In drives of this type where the pinion is traversed longitudinally intomesh with the engine gear by acceleration of lascrew shaft, it iscustomary to provide some means for relieving abutting or jammingconditions which sometimes occur when the teeth of the pinion collidewith the teeth of the engine gear. Such means is usually in the form ofa longitudinally yielding connection between the starting motor andpinion which permits the pinion to pause in its traversal and providetime for the torque from the screw shaft to build up and index thepinion into proper registry with the tooth spaces of the engine gear. Inthe patent to4 McGrath, 1,822,163, the same problem is solved byproviding means extraneous to the threaded connection for indexing thepinion when its longitudinal movement is interrupted by tooth abutmentwith the engine gear.

It is an object of the present invention to provide a starter drivehaving novel means for indexing the pinion in case its meshing movementis arrested.

It is another object to provide such a device in which the indexingmeans is positive in its action and permits no yfree lost motion of thepinion.

It is another object to provide such a device in which the indexingmeans is incorporated in the body of the drive without requiring anyadded or extraneous elements.

Further objects and advantages will be apparent from the followingdescription taken in connection with the accompanying drawing in which:

Fig. 1 is a side elevation partly broken away and in section `of apreferred embodiment of the invention showing the parts in idleposition.

Fig. 2 is a similar view showing the parts in cranking position.

Fig. 3 is a similar view showing the .parts in the positions assumed incase of tooth abutment between the drive pinion and engine gear; and

Fig. 4 is a side elevation of the drive rotated by 90 from the positionillustrated in Fig. 3.

In Fig. 1 of the drawing there is illustrated a power shaft I on which adriving clutch member 2 is xedly mounted as by means'of a cross pin 3retained is position by a, ring 4. Clutch member 2 has overrunningclutch teeth 5 adapted to engage corresponding teeth 6 on a screw 55 1Claim. (Cl. 74-7) shaft I which is slidably journalled on thev powershaft. l -Y A pinion 8 is journalled on the power shaft I forlongitudinal movement into and out of mesh with an engine gear 9. A cupII is rigidly mounted at one end on the pinion as indicated at I2, andat its other end is provided with aradial flange I3 which is anchored asindicated at I4 in the open end of a barrel member I5 enclosing thedrive. The barrel I5 is provided with a pair of inclined or spirallyarranged slots I 6 (Fig. 4), and a control nut Il is threaded on thescrew shaft I and provided with a radial flange I8 having diametricallyarranged lugs I9 extending into and having a loose sliding t in thespiral slots IB. Means for normally maintaining the `control nut withits lugs I9 at the left hand ends of the slots I6 and yfor yieldablyresisting longitudinal movement of the control nut to the right in thebarrel I5 is provided in the form of a cylinder 2I of elasticallydeformable material such as rubber, seated at one end on the control nutagainst the Iiange I8 and at its other end vbearing against the radialflange 22 of a ferrule 23 which is clamped against the flange I3 ofsleeve II by crimping over the end of the barrel I5 as shown at I4.

The barrel I5 is provided with a reduced extension 24 terminating in aninwardly directed flange 25. An anti-drift spring 2B bears at one endagainst the ange 25 of the barrel, and at its other end against a flange2l of ring Ii on which it is seated.

In operation, starting with the parts in the positions illustrated inFig. 1, rotation of the power shaft I in the direction -of the arrow (a)causes the screw shaft I to be rotated by reasonof its clutch connection5, 6 with the drive clutch member 2. Control nut Il is thereby traversedto the right. moving the barrel I5, cup II and pinion 8 through therubber cylinder 2| until the pinion is meshed with the engine gear 9whereupon the flange 25 of the barrel engages the driving clutch member2 as shown in Fig. 2. Further longitudinal movement of the control nutcauses compression of the rubber cylinder, whereby the control nut I'Iis yieldably constrained to rotate with the screw shaft 1, whichrotation is transmitted by lugs I9 to the barrel I5 and pinion 3.

If, during the meshing mov-ement, a tooth of the pinion abuts against atooth of the engine gear, the movement of the pinion is arrested whilethe control nut II continues to move forward compressing elastic member2| as shown in Fig. 3. Inasmuch as the slots I6 in the barrel 3 areinclined or skewed as shown in Fig. 4, the consequent longitudinalmovement of the lugs I9 of the control nut in the slots I6 causes thebarrel, and consequently the pinion 8, to be indexed by the cammingaction of the lugs in the slots so as to bring the teeth of the pinioninto proper registry with the tooth spaces of the engine gear. As soonas this happens, the expansion of the elastic member 2| snaps theypinion into initial mesh, and meshing and cranking proceed as usual.

When the engine starts, the acceleration of th pinion, barrel, andcontrol nut with' 'respect to rotary inertia is dissipated.

shaft, a pinion slidably journaled on the power shaft for movement intoand out of mesh with an engine gear, a. barrel member surrounding thescrew shaft, xed at one end to the pinion and slidably journaled at itsother end on the power shaft, a control nut on the screw shaft having aninclined driving connection to the barrel, and yielding means in thebarrel opposing longitudinal movement of the nut on the barrel; in whichthe barrel is provided with diametrically arranged spiral slots, and thecontrol nut is formed with .radially extending lugs loosely tting in thespiralslots, and the yielding means is arranged between thelcontrol nutand pinion so as 'oo opvposelongitudinal movement of the control nut inthe barrel toward the pinion.

Although but one form of the invention vhas been shown and described indetail, it will be understood that changes. may he made in the designand arrangement of the parts without departing from thespiritofthe.:,'uiyer 1ti0n.,-v

Iclam: Y, c i t ,Y z In anv engine, starter driveA 21.12QYSershaftL kascrew shaft .meenten thereQn, means for QQrlf nesting the scremshaittorqtate with the pow?? ARTHUR R. TOBIAS.

REFERENCES CITED The following references are of record in the le. ofthisv patent:

UNITED STATES PATENTS

